<%@ page language="java" contentType="text/html; charset=UTF8" pageEncoding="UTF8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<%@ page import="java.util.Date" %>
<html>
<head>
    <meta http-equiv="Content-Type" content="t/html; charset=UTF8">
    <title>欢迎登陆</title>
</head>
<body>
<c:if test="${msg == null}">msg is null </c:if>

<c:choose>
    <%-- //调试了好久,之前就写的${ null == msg} or ${empty msg} --%>
    <c:when test="${'[null]' == msg}">你还未登陆!</c:when>
        <c:otherwise>
            <h2>欢迎你:</h2>
            <c:out value="${msg}" />
        </c:otherwise>
</c:choose>

</body>
</html>
